References for Romans 4:9

10
Under what circumstances was it credited? Was it after he was circumcised, or before? It was not after, but before!

11
And he received the sign of circumcision, a seal of the righteousness that he had by faith while he was still uncircumcised.4 So then, he is the father5 of all who believe6 but have not been circumcised, in order that righteousness might be credited to them.

References for Romans 4:15

16
Therefore, the promise comes by faith, so that it may be by grace13 and may be guaranteed14 to all Abraham's offspring--not only to those who are of the law but also to those who are of the faith of Abraham. He is the father of us all.15